Silencer



| Jan. 7, 1936. 5 Q DBE 2,026,795 I SILENCER 1 Filed July 25, 1934 IN VENTOR.

A. BY M47 My ATTORNEY.

Patented Jan. 7, 1936 2,026,795

UNITED STATES PATENT OFFICE SILENCER Sidney Oldberg, Detroit, Mich.

Application July 25, 1934, Serial No. 736,862

Claims. (01. 137-160) This invention relates to silencers and more forward with the gases immediately enter the resparticularly to silencers used in connection with onating chamber 35 and those sound waves of gases exhausted from internal combustion enthe frequencies to which the resonator is responsgines. ive become tuned out. The double wall con- 5 An object of the invention'is to provide a rigid struction with the annular space between the and strong silencer which is eflicient, though two shells 2 and I8 tends to cushion or muflle the cheap and economical to manufacture. sounds formed in the resonator and make the ac- Other objects and features of the present intion of the silencer quiet. The action of the resvention will be'readily apparent to those skilled onator 36 on the outlet end has prac i a y the 10 in the art upon reference to the following detailed same virtues, tending to further reduce the 10 description of embodiments of the same, refersound waves accompanying the exhaust gases.

ence being had to the appended drawing. The concentric construction of the two shells In the drawing, 2 and IS with their headers 4 and 6 make a very Figures 1 and 2 are longitudinal elevational ri id structure which is at the ame time v ry section views of embodiments of the invention. economical to manufacture. The construction 15 Referring to the drawing, it will be seen that here shown is superior to known constructions the silencer of Figure 1 is preferably constructed ause of the fact that the resonators are in the from a cylindrical shell 2 having its ends closed nter. beca e it pr v es h p n by inserted end headers 4 and 6. Centrally 10- ause th damp ng a t r s n t v y high, nd

cated in the inlet and outlet end headers are a e he a s re m ily cooled. being 20 positioned the inlet d tlet tubes Ill-l2, A conducted around the cool resonators to the outnular shoulders formed on the headers 4 and 6 side of the silencer. form abutments upon which is positioned an in- Referring to Figure 2 f e drawing, there is her shell la, the latter preferably being concenshown a second embodiment of the invention.

trically nested within the outer shell 2. It is aps as n ut Shell the end flan es 4 d 6. 25 parent that this structure forms an annular space and the inlet and outlet tubes In and i2, pracor volume 20 between the outer and inner shells tically the same as in the embodiment just dewhich is utilized to form a passageway for the scribed. This embodiment also employs a shell gases which course therethrough from the inlet l8, and diaphra s 22 a d 5', providing p tube to the outlet tube. sion chambers 33 and 34 adjacent the inlet and 30 The inner shell I8 is divided by means of diaoutlet tubes. It differs from the one shown in phragms 22-2426 into four volumes, two of Figure 1 in that a third, concentrically positioned, which (33-3T) are immediately adjacent the inshell 49 is added to the structure to form an let and outlet tubes and form end expansion annular space inside the shell Hi, the shell 49 35 chambers for the coursing gases. Between these being held in position by annular shoulders 50 on 35 are positioned two'closed spaces 35 and 36 which the diaphragms 2226. The shell 49 is rigidly form the resonator chambers for the silencer. positioned between these two diaphragms, and The mouths of the resonating chambers are is further suppo by annular rings 5| D formed by perforating the diaphragms 22-26 tioned in the annular volume between the two 40 and placing therein the tubes 38, these being of shells l8 and 49, the annular rings 5| having a 40 any desired length. further function in that they divide the annular The gas expansion chambers 33-34 are in volume between the two shells l8 and 49 into communication with the annular space 20 sections 52 which form absorption chambers for through holes 40 in the inner shell l8. Thus the the noises accompanying the gases coursing gases entering the silencer by the inlet tube l0 through volume 20, which chambers are in com- 45 are directed through the holes 40 into the annumunication with the coursing volume 20 through lar space 20, from whence they are led to the holes 53 in the wall of the shell l8. In this emexpansion space 34, adjacent the outlet, through bodiment the central chamber within the shell holes 40, flowing out therefrom through the out l9 forms two resonators 5455, separated by a let tube l2. diaphragm 56. 50

It will be seen that original impulses of sound Under certain circumstances, it may be desired accompanying the gases through the inlet H) are to dispense with the dual resonator construction. deadened by the resonator chamber 35 whose In this case, the diaphragm 56 is dispensed with mouth or inlet 33 is practically concentric with and the header 26 within the shell I8 is closed 55 the tube I0. Hence the sound waves traveling completely, eliminating the resonator tube 38 on 55 at the inlet end by the resonator tube 38 positioned there.

In the embodiment shown, the coursing gases enter the silencer through the tube l0 and enter the expansion chamber 33, the resonator as within the shell 49 tuning out the greatest portion of the accompanying sound waves. The gases then flow through the holes M in the wall of the shell l8 into the annular volume 20, where they flow past the holes 53 of the absorption chambers 52. At this point the sound waves, still accompanying the coursing gases, are further reduced by absorption in the chambers 52. The coursing gases then flow through the holes in in the wall of the shell l8 on the outlet end into the expansion chamber 36. When the gases are in the expansion chamber, the noises may be reduced still further through the action of the resonator chamber 55. The gases then flow smoothly through the outlet tube l 2 to the atmosphere.

Where the shell 59 encloses only one resonating chamber, it is clear that no further diminution of noises will be accomplished at the outlet end, and the coursing gases will flow from the expansion chamber 36 into the atmosphere through outlet tube I2, without their sound waves being tuned out at the outlet.

The construction shown in Figure 2 will be more rigid than the one shown in Figure 1, and yet be economical in manufacture.

Now having described preferred embodiments of the invention, reference will be had to the following claims for a \determination of the scope of the invention.

What I claim is:

1. In a silencer, two nested casings, an inlet of less diameter than the innermost casing opening directly thereinto, an apertured diaphragm in the innermost casing remote from said inlet dividing the innermost casing longitudinally into an expansion chamber into which the inlet opens, and a resonance chamber in communication with the expansion chamber but otherwise closed, there being a communication from said expansion chamber into the volume between the casings, and an outlet for said volume remote from the aforesaid communication.

2. In a silencer, means providing an expansion chamber into which opens the gas flow inlet, a resonance chamber in communication with said expansion chamber, and an annular gas flow volume around said chambers, the expansion chamber being in communication with said 5 volume.

3. In a silencer, two nested casings, with the innermost one having three diaphragms dividing it longitudinally into two end chambers between which are two intermediate chamberaeach end 10 chamber being in communication with the adjacent intermediate chamber through a hole in their separating diaphragm, the intermediate chambers being otherwise closed, an inlet for one end chamber, and an outlet for the other end 15 chamber, there being a communication between each end chamber and the volume between the pair of casings. I

4. In a silencer, two nested casings, an inlet of less diameter than the innermost casing opening 20 directly thereinto, an apertured diaphragm in the innermost casing remote from said inlet dividing the innermost casing longitudinally into an expansion chamber into which the inlet opens, and a resonance chamber in communication with the 25 expansion chamber but otherwise closed, there being a communication from said expansion chamber into the volume between the casings and an outlet for said volume remote from the aforesaid communication, the innermost casing 00 being double walled to provide an annular sound wave absorption space communicating with the annular space between the casings through apertures in the outer wall of the innermost casing.

5. In a silencer, two nested casings, with the 5 innermost one having three diaphragms dividing it longitudinally into two end chambers between which are two intermediate chambers, each end chamber being in communication with the adjacent intermediate chamber through a hole 40 in their separating diaphragm, the intermediate chambers being otherwise closed, an inlet for one end chamber, and an outlet for the other end chamber, there being a communication between each end chamber and the volume between the 45 pair of casings, the innermost casing being double walled to provide an annular sound wave absorption space communicating with the annular space between the casings through apertures in the outer wall of the innermost casing. 50

SIDNEY OLDBERG. 

